(Reuters) - Jordan Spieth sent a message to his critics he had not made a mistake by warming up for the British Open with a tournament in the United States and showed he was ready to challenge for the title by claiming the John Deere Classic in a playoff on Sunday.
Spieth, already the winner of this year's Masters and U.S. Open, defeated unheralded fellow-American Tom Gillis on the second playoff hole at TPC Deere Run in Silvis, Illinois.
The victory was the world number two's fourth of the season and a return win at the tournament where he claimed his first PGA title in 2013.
Playing the 18th hole for a third time in a half-hour, Spieth used a short par putt for the victory over the 46-year-old Gillis, who was making his 172nd career PGA Tour start.
Both had parred the first extra hole after ending regulation at 20-under-par.
"It was a really, really fun day. Not the best start, but certainly OK with the outcome," Spieth told CBS.
American Zach Johnson (65) and New Zealand's Danny Lee (67) tied for third at 19-under 265.
The 21-year-old Spieth had gotten the round off to an inauspicious start when he bogeyed the first and third holes before recovering to make the turn at even par.
After a bogey on the 11th he birdied four of the next five holes from 13th on to force a playoff a day after a sizzling 61 put him atop the leaderboard.
Gillis surged into the lead with five birdies in his first six holes and added another at the eighth before giving a stroke back with a bogey at the ninth.
He added more birdies at the 10th, 12th and 15th before a bogey at 16 gave Spieth a chance.
(Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Greg Stutchbury)